Process for manufacturing sulphur dyestuffs



Patented Mar. 20, 1934 {UNITED STA PROCESS FOR TES ' PATENT OFFICE,

MANUFACTURING SULPHUR DYESTUFFS Delaware No Drawing. Continuation of application Serial No. 328,058, December 22, 1928. This application March 13, 1931, Serial No. 522,512.

Germany December 27, 1927 3 Claims.

This application is a continuation of our application Serial No. 328,058,filed December 22, 1928. It is well known that the production of sulphur dyestuffs derived from indophenols or leucoindo- 5 phenols needs frequently an exceedingly long boiling with aqueous or alcoholic polysulphide solutions for obtaining useful dyestuffs and for reaching the maximum of dyestuff formation.

Now we "have found a new improved method for abbreviating essentially the duration of the sulphuration process when adding to the reaction mass an oxidizing agent at a suitable moment which depends as we have found on the character of the starting material used and on the sulphurizing agent applied. As oxidizing agents besides air particularly nitrocompounds of the formula XNO2, wherein X means an organic radical or a metal, such as nitrobenzene, nitrophenol, ethylnitrite and as inorganic oxidizing agents with the same effect alkali nitrites are suitable. The most efiective quantity of the oxidizing agent as well as the most favorable moment of adding the oxidizing agent may be advantageously ascertained by previous tests.

'The especial technical efiect of our improved process consists in the fact, that the formation of the dyestuiis is essentially accelerated, and in the further fact, that, the leucocompounds of sulphur dyestufis formed as primary reaction products are immediately converted into the dyestuffs themselves, whereas this important endphase according to the usual process is only obtained by a long heating of the reaction mass.

As a consequence of these facts the dyestuffs obtained according to our process are distinguished by a better solubility and a very pure shade compared with the products obtained according to the usual process of sulphuration.

When combining our present process with the step of using hydroaromatic hydroxycompounds as solvents for the sulphuration process as described in our U. S. Patent No. 1,759,261, filed June 26, 1928, especially favorable results are obtained.

In order to further illustrate our invention the following examples are given, the parts being by weight and all temperatures in centigrade degrees; but we wish it however to be understood that our invention is not limited to the examples given, nor to the exact conditions stated therein.

Example 1 100 parts of sodium sulphide of 60% strength, 150 parts of sulphur and about 225 parts of butylalcohol are boiled in an apparatus provided with a reflux condenser in order to form the polysulphide. Then to this solution 100 parts of 3-(4'- hydroxyphenyl) -aminocarbazol are added and the mixture is boiled for about 8 hours. Then for about 2 hours air is blown in, then the mass is diluted with about 500 parts of water and slightly acidulated. The butyl-alcohol is removed by steam distillation and the precipitated dyestuff is filtered off. For removing some adhering sulphur the moist'filter-good may be treated with a dilute sodium sulphide solution or when previously dried the residue may be extracted with suitable solvents such as carbon disulphide. The dyestufi thusobtained corresponds in its properties with the dyestufi described in U. S. Patent 956,348. The yield is substantially increased compared with the process carried out in the same manner but without blowing in air.

Example 2 100. parts of sodium sulphide of 60% strength,

150 parts of sulphur and about 400 parts of alcohol of 95% strength are boiled in an apparatus provided with a reflux condenser in order to form the polysulphide. Then to this solution 100 parts of 3-(4'-hydroxyphenyl) -aminocarbazol are addsulphide solution or when previously dried the The alcohol is distilled ofi,

residue may be extracted with suitable solvents such as carbon disulphide. The dyestufi thus obtained in an especially good yield and purity corresponds in its properties with the dyestuif def scribed in U. S. Patent No. 956,348.

Example 3 To a solution of 80 parts of sodium sulphide of 60% strength and 160 parts of sulphur in about 400 parts of alcohol 100 parts of 3-(4'-hydroxy-;

phenyl)-amino-9-ethyl-carbazol are added and the mixture is heated to boiling for about 40 hours in an apparatus provided with a reflux condenser. Then a solution of 10 parts of sodium nitrite in about 100 parts of water is added,

whereby the dyestuff separates from the brown liquor. It is isolated in the manner described in Example 1. The dyestufi thus obtained is identical in its general properties with the dyestufi of llO U. S. Patent No. 966,092 but it is superior astoits tinctorial intensity.

Example 4 A mixture of 100 parts of crystallized sodium sulphide, 200 parts of water'and 4.0 parts ofisul phur is mixed with 22.5 parts of 4-amino-3; methyl-4'-hydroxy-diphenylamine and the whole is heated to boiling for about 20 hours atabout 105-110 in an apparatus provided with a reflux condenser. After addition of a. solution of'2 parts of sodium nitrite in about parts of water, heating is continued for about 2 hours, whereby the dyestuff separates as a compact mass. Then, the. mass is diluted with about the tenfold quantity of.

Example 5 parts of sodium sulphide of 60% strength, v

parts of sulphur and 200 parts of methylcyclohexanol are heated at 110-120" while stirring. Then during about a quarter of an hour 25 parts of 4-hydroxy-diphenylamine are introduced. and the mass is heated in an apparatus provided with a descending condenser, until the water has beenentirely, distilled off, and then for "about further 3 hours while using a reflux condenser. The mass: is cooled down to about 110- 120 and a mixture of; 4 parts of nitrobenzene and 20 parts of methyl-cyclohexanol is added. After heating for a short time it is diluted with water, feebly acidulated and the methyl-cyclohexanol is expelled by steam. Then thedyestufi is filtered ofiand, dried, It isidentical with the dyestufi .obtained according to U. S. application Serial No. 726,121 (of. U. S. Patent 1,098,259). Also in this case theaddition of nitrite increases the yield and vthe tinctorial power and causes an essential abbreviation of the duration of the process.

' Example 6 1c .2 5parts of sodium sulphide of strength,

30 parts of sulphur and 120 partsor methylcyclo-hexanol are heatedwhile stirringto about 120? until a complete solution occurs. Then quickly 20 parts of 4-phenylamino-4-hydroxydiphenylamine are added and the mixture is at firstheated in ..an apparatus provided with a descending condenser until the Water contained in the mass is distilled oiT, and then heating is continuedforabout an hour at about 160". Then the mass is cooled down to about 110 and 2 /2 parts of-nitrobenzene are added, whereby the dyestuff quickly separates from the brown solution. After dilution with cold water the methyl-cyclohexanol isexpelled by, steam and the dyestuff is isolated in. the usual manner by acidulating the mass or-bymeans of a stream of air. The dyestuif thus-formed is identical with that of U. S. Patent 723,154, but it is obtained according to our present process in a better yield, being also super qr. asto the solub i -1 Y x Wewish it tobe. understood that in the fol,- lowing claimsthe term indophenol compounds includes the indophenols and their leuco compounds.

We. claim:

1. An improved process which comprisesadding during the process of sulphuration of a paraaminophenol derivativean oxidizing agent ofthe group consisting of air'and nitro compounds to the sulphuration mass comprising an indophenol compoundand an alkali metal polysulphide.

2. An improved process whiohcomprises add ing during the process of sulphuration of -a pa raaminophenol derivative anoxidizing agent of the general formula:

XNOz,

whereinX means a monovalent metal or monovalent hydrocarbon radical, to the sulphuration mass comprising an indophenol compound and an alkali metal polysulphide.

3. An improved process which comprises adding during the process of sulphuration of a paraaminophenol derivative an alkali nitrite to the sulphuration mass comprising an indophenol compound and an alkali metal polysulphide.

GEORG KALISCI-IER. HEINRICH BITTER. 

